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- Botany (5)
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- Cuscuta (2)
- Nodulation (2)
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- Parasitic plants (2)
- Plant systematics (2)
- Spanish River Carbonatite (2)
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Articles 1 - 26 of 26
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Discerning Friend From Foe: Systematic Revision Of Cuscuta L. Section Indecorae Using A Combined Ecological, Morphometric, And Phylogenetic Approach., Corey Burt
Theses and Dissertations (Comprehensive)
The genus Cuscuta (Dodder; Convolvulaceae) are obligate parasitic plants. In one clade known as section Indecorae, there are species which are considered pests that pose significant threats to agricultural crop production, while other species are rare or known only from historical records. Section Indecorae contains three species: C. coryli, C. warneri, and C. indecora (the latter with three infraspecific taxa: var. indecora, var. longisepala, and var. attenuata). The systematics of section Indecorae are not currently resolved. Cuscuta indecora has a long and complicated taxonomic history with many infraspecific varieties described, and …
Winter Dynamics Of Storm Water Management Ponds And Winter Tolerance In Three Aquatic Plant Species, Patrick Strzalkowski
Winter Dynamics Of Storm Water Management Ponds And Winter Tolerance In Three Aquatic Plant Species, Patrick Strzalkowski
Theses and Dissertations (Comprehensive)
The vast majority of the research into the performance of stormwater management ponds (SWMPs) has been performed in warm regions or during the warmer seasons in temperate regions. It is presumed that SWMPs are inactive in the winter as any potential stormwater is trapped in snow and ice. The main goal of this thesis was to test this presumption and to study the dynamics and performance of three SWMPs during the winter. Remote water level loggers were installed into the three SWMPs and daily grab samples from the influents and effluents were taken and analyzed for total phosphorus (TP), chloride, …
Investigating The Effects Of Disturbance And Competition On Establishment, Growth, And Reproduction Of The Endangered Ripariosida Hermaphrodita, Daniel Engelking
Investigating The Effects Of Disturbance And Competition On Establishment, Growth, And Reproduction Of The Endangered Ripariosida Hermaphrodita, Daniel Engelking
Theses and Dissertations (Comprehensive)
Ripariosida hermaphrodita (Virginia Mallow) is a perennial riparian plant with broad, maple-like leaves. It grows up to three meters high and is often found in large clonal patches, but sexually reproduces readily. While this plant may seem like a redoubtable competitor when growing in large colonies, it is declining across its range in North America. The only known occurrences in Canada are in southern Ontario. Prior to this study, no new populations had been recorded even though one of the known populations produces copious amounts of viable seed with potential to disperse. There are many hypotheses for its rarity, but …
Changes In Plant Community Composition, Structure, And Function In Response To Permafrost Thaw, Katherine Standen
Changes In Plant Community Composition, Structure, And Function In Response To Permafrost Thaw, Katherine Standen
Theses and Dissertations (Comprehensive)
Air temperature is increasing at three or more times the global average in high latitudes, causing widespread permafrost thaw across the boreal biome. Since the boreal biome stores 30-40% of global terrestrial carbon (C), of which about 30-45% is found in permafrost soils, this temperature increase could cause a large efflux of C to the atmosphere. Climate warming and permafrost thaw are also expected to alter plant community composition and productivity and, given the link between plant functional traits and ecosystem C fluxes, may alter overall ecosystem function. Across the boreal biome of western Canada, we know surprisingly little about …
Diversity And Evolution Of Inflorescences In Cuscuta, Morgan Glofcheskie
Diversity And Evolution Of Inflorescences In Cuscuta, Morgan Glofcheskie
Theses and Dissertations (Comprehensive)
Cuscuta (dodder) includes ca. 200 species of plant obligate stem parasites with both ecological and economical significance. Inflorescences have been historically used in Cuscuta for species descriptions and identification keys, but no comprehensive study exists to date. The main objective of this study was to survey the diversity of inflorescences, and to understand their evolution and possible form-function relationships. The inflorescence architecture of 132 Cuscuta taxa was analyzed using herbarium specimens, and eight species were grown to study their inflorescence development. Inflorescence traits were mapped into a genus phylogeny obtained from a combined analysis of nuclear ITS and plastid trnL-F …
Wildlife Forage Recovery Following Boreal Wildfire, Alexis Jorgensen, Jennifer Baltzer
Wildlife Forage Recovery Following Boreal Wildfire, Alexis Jorgensen, Jennifer Baltzer
Theses and Dissertations (Comprehensive)
Climate change is altering the boreal wildfire regime through increases in the extent and severity of burning and reductions in fire return intervals. These changes can alter the regeneration trajectory of canopy species and ground vegetation, with implications for wildlife habitat. There is some uncertainty about the timelines of when different animal species will use burned areas as their preferred forage taxa recover following fire, and how such recovery is mediated by environmental factors. Here, we aim to address these knowledge gaps through the following questions: 1) What are the main forage types consumed by boreal wildlife and how much …
Effects Of Phosphorus On Mycorrhizal Colonization Of Wetland Plants Under Natural And Controlled Conditions, Miriah Tucker
Effects Of Phosphorus On Mycorrhizal Colonization Of Wetland Plants Under Natural And Controlled Conditions, Miriah Tucker
Theses and Dissertations (Comprehensive)
An important symbiotic relationship that forms in wetland environments occurs between plants and arbuscular mycorrhizal fungi (AMF). In terrestrial communities AMF colonization is limited by phosphorus; excessive phosphorus can lead to an uncoupling of the relationship. Few studies have examined the relationship between AMF and phosphorus concentration in wetland plants. The studies that have, found a decrease in AMF colonization at phosphorus concentrations as low as 0.03 mg/L P, however, methodological issues limit the interpretation of these results. To address this, a field and greenhouse study were completed using more realistic exposure conditions, field deployable assays (FDA), and natural intact …
Competition Or Facilitation: Examination Of Interactions Between Endangered Sida Hermaphrodita And Invasive Phragmites Australis, Samantha N. Mulholland
Competition Or Facilitation: Examination Of Interactions Between Endangered Sida Hermaphrodita And Invasive Phragmites Australis, Samantha N. Mulholland
Theses and Dissertations (Comprehensive)
Virginia Mallow (Sida hermaphrodita) is a perennial herb of the Malvaceae family that is native to riparian habitats in northeastern North America. Throughout most of its geographical distribution however, it is considered threatened and only two populations are known from Canada. The biology and ecology of S. hermaphrodita are still poorly understood and although few studies have been performed to determine the factors that contribute to the species rarity, it is considered threatened potentially due to the loss of habitat caused by exotic European Common reed (Phragmites australis subsp. australis) invasion. Allelopathic and phytotoxic conditioning of …
Context Is Everything: An Investigation Of Spanish River Carbonatite And Its Effects On Soil-Plant-Microorganism Systems, James Mc Jones
Context Is Everything: An Investigation Of Spanish River Carbonatite And Its Effects On Soil-Plant-Microorganism Systems, James Mc Jones
Theses and Dissertations (Comprehensive)
With growing concerns about agricultural sustainability and food security, the use of rock fertilizers and agrominerals is receiving renewed interest. A wide variety of geological resources have been proposed as crop nutrient sources, with silicate rocks the predominant focus. Carbonatite rocks are known to weather more readily than silicate rocks; yet, they have received relatively little attention as it is thought their high Ca and Mg contents hinder effective nutrient release. However, there is strong evidence that the nutrients within carbonatite rocks are easily accessible to plants, and that these rocks have noticable effects on crop plant growth. Here I …
Going Back To The Soil: An Integrated Approach To Farming., Renée V. Christie
Going Back To The Soil: An Integrated Approach To Farming., Renée V. Christie
Theses and Dissertations (Comprehensive)
Agricultural productivity is often constrained by nutrient availability; as such, copious amounts of synthetic fertilizers are applied to maintain productivity. However, the intensive use of synthetic fertilizers has reduced the capacity of the soil to carry out crucial roles such as nutrient cycling because of shifts in the microbial community composition and structure. In addition, much of the applied synthetic fertilizers become lost to the environment through run-off, which contributes to soil degradation. With the increasing demand on agricultural systems to provide food and fibre and the adverse impacts of agricultural production on the soil resource, amendments that support soil …
Diversity And Evolution Of Seeds In Cuscuta (Dodders, Convolvulaceae): Morphology And Structure, Magdalena Olszewski
Diversity And Evolution Of Seeds In Cuscuta (Dodders, Convolvulaceae): Morphology And Structure, Magdalena Olszewski
Theses and Dissertations (Comprehensive)
Cuscuta is a genus of nearly 200 obligate stem parasites with a nearly cosmopolitan distribution and considerable agricultural and ecological significance. Dodder seeds are considered “unspecialized”, with no morphological adaptations towards particular dispersal vectors; however, the seed coat anatomy has recently suggested an adaptation to endozoochory. This is the first attempt to provide a genus-wide overview of the diversity in morphology and anatomy of Cuscuta seeds, together with an assessment of the water gap and exploration of various form-function relationships. I surveyed 104 species belonging to all four Cuscuta subgenera. Seeds of the species of the first infrageneric dodder …
Drivers Of Post-Fire Vascular Plant Regeneration In The Conifer-Dominated Boreal Forest Of Southern Northwest Territories, Alison White
Drivers Of Post-Fire Vascular Plant Regeneration In The Conifer-Dominated Boreal Forest Of Southern Northwest Territories, Alison White
Theses and Dissertations (Comprehensive)
In recent years, climate warming has led to an increase in the severity and frequency of naturally occurring fires in boreal ecosystems globally. In 2014, an unprecedented 3.4 million hectares of boreal forest burned in the Northwest Territories (NWT). While much research has focused on post-fire succession of serotinous tree species such as Picea mariana (black spruce) and Pinus banksiana (jack pine), the understory community of vascular plants play an important role in ecosystem functioning but less is known about the response of this component of the system to changing fire regimes. Regeneration strategies such as the ability to resprout …
Influence Of Topography And Moisture And Nutrient Availability On Green Alder Function On The Low Arctic Tundra, Nt, Katherine Louise Black Ms., Jennifer Lynn Baltzer Dr.
Influence Of Topography And Moisture And Nutrient Availability On Green Alder Function On The Low Arctic Tundra, Nt, Katherine Louise Black Ms., Jennifer Lynn Baltzer Dr.
Theses and Dissertations (Comprehensive)
The Arctic has warmed by at least 3°C over the past 50 years and this rapid warming is expected to continue. Climate warming is driving the proliferation of shrubs across the tundra biome with implications for energy balance, climate, hydrology, nutrient cycling, and biodiversity. Changes in tundra plant water use attributable to shrub expansion are predicted to increase evapotranspirative water loss which may amplify local warming and reduce run-off. However, little is known about the extent to which shrubs will enhance evapotranspirative water loss in these systems. Direct measures of shrub water use are needed to accurately predict …
An Assessment Of How Plant And Mycorrhizal Communities Have Been Affected Along A Mine-Impacted Watershed In The Northwest Territories, Kevin Maccoll
An Assessment Of How Plant And Mycorrhizal Communities Have Been Affected Along A Mine-Impacted Watershed In The Northwest Territories, Kevin Maccoll
Theses and Dissertations (Comprehensive)
Giant Mine is an inactive gold mine located nine kilometers north of Yellowknife, Northwest Territories. Giant Mine has been the source of arsenic trioxide for the Baker Creek watershed since it opened over 60 years ago. Although arsenic levels in the creek are above the limits considered to be biologically relevant, there is no concrete evidence that plants and mycorrhizae have actually been affected. This study provides an initial assessment of the impacts mining activity at Giant Mine has had on plants and mycorrhizae in the Baker Creek watershed. Nine sites were sampled around Giant Mine: five sites downstream from …
Diversity And Evolution Of Fruits In Cuscuta (Dodders; Convolvulaceae), Anna Ho
Diversity And Evolution Of Fruits In Cuscuta (Dodders; Convolvulaceae), Anna Ho
Theses and Dissertations (Comprehensive)
Cuscuta (dodder) is a genus of roughly 200 species of obligate stem parasites with sub-cosmopolitan distribution. The fruit, generally regarded as a capsule, has a thin pericarp containing one to four seeds and opening at the base (circumscissile dehiscence; DE), or remaining closed (indehiscent; IN). IN has evolved multiple times in Cuscuta from DE, and is most common in the North American clades of subgenus Grammica. In addition, some species produce fruits that open irregularly. Characteristics pertaining to the fruits of Cuscuta are important as their seeds contribute most to their distribution and prevalence across the globe, and their reduced …
Spanish River Carbonatite: Its Benefits And Potential Use As A Soil Supplement In Agriculture, James J
Spanish River Carbonatite: Its Benefits And Potential Use As A Soil Supplement In Agriculture, James J
Theses and Dissertations (Comprehensive)
A critical problem facing agriculture today is being able to consistently and sustainably provide plants with adequate nutrients for growth. With this problem being exacerbated by the ever-increasing human population, new perspectives and techniques are required to ensure global food security. In order to fully realize potential solutions, however, plant growth and nutrition cannot be exclusively focused upon. The soil-microorganism-plant system is comprised of many interconnected and interdependent processes that together support plant growth: it is upon these processes that the focus must be placed. In this work, the agromineral Spanish River Carbonatite (SRC) is characterized using the framework of …
A Structure-Function Analysis Of The Arabidopsis Chloroplast Import Protein Attic20, James H. Campbell
A Structure-Function Analysis Of The Arabidopsis Chloroplast Import Protein Attic20, James H. Campbell
Theses and Dissertations (Comprehensive)
Arabidopsis thaliana protein Tic20 (atTic20) is a member of the translocon at the inner envelope membrane of chloroplasts. Evidence to date suggests it is part of the main preprotein conducting aperture in the complex, but its exact role is still debated. To help characterize its role, a protocol optimizing yield and purity of recombinantly expressed atTic20 was developed, and a series of experiments was performed to examine its secondary structure and its ability to interact with chloroplast transit peptides. The attempt to increase protein yield was successful, with growth at 20oC in the auto-inducing media ZYP-5052 showing the …
Morphology, Structure, Function And Evolution Of Infrastaminal Scales In Cuscuta (Convolvulaceae), Stephanie Riviere
Morphology, Structure, Function And Evolution Of Infrastaminal Scales In Cuscuta (Convolvulaceae), Stephanie Riviere
Theses and Dissertations (Comprehensive)
Cuscuta (dodder, Convolvulaceae) is a genus of about 200 species of obligate stem parasites of cosmopolitan distribution. Infrastaminal scales (IFS) are staminode-like formations that surround the ovary in the flowers of dodders. Their morphological diversity has historically provided some of the most useful taxonomic diagnostic characters at the species-level, however, their function had not been determined. I performed a comparative study of the IFS in 147 taxa using light, scanning and transmission electron microscopy, and results were analyzed in relation to a Cuscuta phylogeny obtained from a combined analysis of rbcL and 26S rDNA gene sequences. To test the hypothesis …
The Evolution Of Sexual Reproduction In Cuscuta (Convolvulaceae), Michael Wright
The Evolution Of Sexual Reproduction In Cuscuta (Convolvulaceae), Michael Wright
Theses and Dissertations (Comprehensive)
Cuscuta (Convolvulaceae), the dodders, is a genus of ca. 200 species of obligate stem parasites distributed across a great diversity of habitats worldwide. The existence of a handful of species that are dangerous crop weeds has led researchers to historically focus on their growth and control. Consequently, there is a dearth of information about their biodiversity, ecology, and in particular their reproductive biology. This thesis surveys aspects of sex allocation, floral evolution, floral rewards for pollinators, and mechanisms of reproductive assurance across the genus. I demonstrate that Cuscuta has evolved a broad spectrum of breeding systems, from obligate selfing to …
The Role Of The Acidic Domain Of The Toc159 Protein Import Receptor Family In Toc Complex Assembly In Arabidopsis Thaliana, Yi Chen
Theses and Dissertations (Comprehensive)
Most chloroplast proteins are encoded in the nucleus and translated in the cytosol with an N-terminal cleavable transit peptide, which can be recognized by the translocon at the outer envelope membrane of chloroplasts (Toc complex). The core Toc complex is composed of two GTPases, Toc159 and Toc34, and the Toc75 channel. atToc159, atToc132 and atToc120 are homologues of the Toc159 family in Arabidopsis, and have been shown to assemble into structurally and functionally distinct Toc complexes. Targeting of atToc159 to the chloroplast outer membrane is mediated by its GTPase (G-) domain. However, the role of the acidic (A-) domain in …
Molecular Studies Of 5-Azacytidine-Induced Early-Flowering Lines Of Flax, Megan A. House
Molecular Studies Of 5-Azacytidine-Induced Early-Flowering Lines Of Flax, Megan A. House
Theses and Dissertations (Comprehensive)
Several early-flowering flax (Linum usitatissimum L.) lines were derived from treatment of germinating seeds with 5-azacytidine in 1990. These lines are also shorter, have fewer leaves, and their DNA is hypomethylated, relative to their corresponding controls. The work presented in this thesis used early-flowering and control lines of the Royal (R) flax genotype, and the Large (L) flax genotroph. Firstly, levels of cytosine methylation were measured over a 24-hour period in the early-flowering line RE2 and its control (RC), using an HPLC method. Secondly, to determine the response of the flax lines to short-day conditions, control and early-flowering …
The Pleiotropic Mutant R50 (Sym16): A Link Between Cytokinin And Starch Metabolism May Explain Its Seed Phenotype, Chengli Long
The Pleiotropic Mutant R50 (Sym16): A Link Between Cytokinin And Starch Metabolism May Explain Its Seed Phenotype, Chengli Long
Theses and Dissertations (Comprehensive)
Cytokinins are a class of adenine-based plant hormones that stimulate cell divisions and are therefore essential for organ growth and development. The role that cytokinin plays in nodulation and that of R50 (syml6) in particular is very complex. In this study, a cytokinin antagonist and a cytokinin oxidase (CKX) inhibitor were used as tools to study the effects of cytokinin perception or cytokinin degradation on nodulation in pea, the cytokinin transduction pathway, especially that induced by CRE1/AHK4, and CKX play a significant role in pea nodulation. Comparison of the full length sequences PsCKX2 cDNAs from Sparkle and R50 …
Insights Into The World Of Pea Nodulation Using The Low Nodulator R50, Scott Clemow
Insights Into The World Of Pea Nodulation Using The Low Nodulator R50, Scott Clemow
Theses and Dissertations (Comprehensive)
Cytokinin oxidase (CKX) is the enzyme responsible for the degradation of cytokinin, a class of adenine-based plant hormones that stimulate cell division, among other physiological processes. The pea mutant R50 is characterized by having a pale leaf phenotype, dwarf stature, few lateral roots, low nodule formation, and elevated levels of endogenous cytokinins in its shoots, roots and nodules. When compared to that of the wild-type Sparkle, total CKX activity is low but the transcript levels of PsCKX1 are significantly higher. In this study, I investigated the expression of PsCKX1 throughout the development of a nodule and the localization of PsCKX1 …
Evolution And Systematic Significance Of Reproductive Structures In The Genus Cuscuta (Dodders, Convolvulaceae): Pollen And Gynoecium, Mark Welsh
Theses and Dissertations (Comprehensive)
The genus Cuscuta (dodders, Convolvulaceae) is one of the most significant lineages of parasitic plants from economic, conservation, and anthropogenic perspectives. Members of the genus are twining stem parasites with no roots, lacking almost completely chlorophyll or its function, and gather required nutrition from their host via specialized haustorial connections. While there are almost 200 described species, problems with species identification exist because many diagnostic characters are restricted to their tiny flowers. Probably contributing to this identification difficulty is the fact that the group has not received taxonomic attention for over 75 years; even knowledge of its basic reproductive biology …
The Growth And Distribution Of The Green Alga Cladophora At Presqu'ile Provincial Park: Implications For Management (Ontario), Dolf Craig Dejong
The Growth And Distribution Of The Green Alga Cladophora At Presqu'ile Provincial Park: Implications For Management (Ontario), Dolf Craig Dejong
Theses and Dissertations (Comprehensive)
The Green alga genus Caldophora is one of the most abundant kinds of algae worldwide, found in both freshwater and marine environments. It prefers nutrient-rich waters and requires a rocky substrate and water movement for growth. When water temperatures reach 22 to 26 C, the alga dies and washes into shore in large mats. Dead Cladophora produces a terrible odour, reduces property values and can alter the taste of drinking water. At Presqu’ile Provincial Park, maximum Cladophora sloughing occurred July 22 1999, the same time as peak summer park visitation begins. This results in the fouling of the Park’s beaches …
Vegetation Pattern And Disturbance Effects In The Subalpine-Alpine Interface, Valley Of The Ten Peaks, Alberta, Katherine J. Miller
Vegetation Pattern And Disturbance Effects In The Subalpine-Alpine Interface, Valley Of The Ten Peaks, Alberta, Katherine J. Miller
Theses and Dissertations (Comprehensive)
There have been several recent calls in the biogeography and vegetation ecology literature to investigate more thoroughly the role of recurrent disturbance or perturbation in the dynamics of subalpine communities, by assessing persistence and change in the dominant species population. In order to study the relationship between conifer regenerative effectiveness, disturbance effects, and the nature of the vegetation pattern, a field study was made of the vegetative cover (composition, abundance, dominance) and its performance (survival, vigour, and reproductive mode) in the upper subalpine zone in the Valley of the Ten Peaks, Banff National Park, Alberta. The occurrence of stresses and …